Devastating storms swept through the South on Wednesday, killing at least 60 people and spawning a tornado that tore through downtown Tuscaloosa, Ala. The evening twister flattened homes and buildings and brought further damage and death to a region already battered by storms.

Across Alabama, at least 50 people were killed by storms on Wednesday alone, according to officials. The Associated Press reported an additional 11 deaths in Mississippi, two in Georgia and one in Tennessee.

The tornado, one of several that struck the state, ripped through Tuscaloosa about 5 p.m. on a northwest path.

It veered past a major medical center, a high school and the campus of the University of Alabama. The extent of the damage was unclear Wednesday evening, but officials said many people were still trapped in homes and buildings. They feared the death toll could rise in the coming days.

Many parts of the state had been on a tornado watch throughout the day, prompting schools, government offices and businesses to shut their doors early or remain closed, Mayor Walter Maddox of Tuscaloosa said in an interview Wednesday evening.

“I believe at the end of the day that will have saved many lives,” he said of the emergency measures. “We have so many reports of damage across the city. We do believe it to be significant.”

Mark Kelly, a spokesman for the Jefferson County Emergency Management Office, said the storm had picked up speed as it barreled out of Tuscaloosa and headed for the western part of the county, passing north of downtown Birmingham, which was battered by another storm early Wednesday morning.

Mr. Kelly said that he had gotten reports of roofs torn from homes, people trapped in buildings, and power lines strewn across interstate roads, but that crews were just beginning to respond. At least 11 people were killed in Jefferson County on Wednesday, “but we expect that number will go up as search and rescue efforts go on through the night and into tomorrow,” he said.

The damage from the tornados was made worse by earlier storms, which left the ground so soaked that instead of the winds just snapping trees and branches, they uprooted entire trees and tossed them onto power lines, said Michael Sznajderman, a spokesman for the Alabama Power Company. He said at least 335,000 customers were without power, and with more storms on the way, “the number of outages could be as high as what we saw with Hurricane Ivan or Hurricane Katrina.”

Photo

Jeremy Abbott examined what remained of his home near Oxford, Miss., on Wednesday.Credit
Bruce Newman/Oxford Eagle, via Associated Press

“It has already surpassed Hurricanes Dennis and Frederick,” he said. “We have line crews on the way from as far away as Illinois to assist in the recovery.”

Power losses were widespread across the University of Alabama, where many students were holed up after the tornado swept just south of the campus.

Emily Crawford, a third-year student at the law school, said she had been preparing for an end-of-semester exam when the tornado swirled by. By nightfall she was still at the law school, which had become a refuge for scores of students, many of whom spoke of devastation in their neighborhoods worse than they had seen reported from Hurricane Katrina.

“It is surreal,” Ms. Crawford said. “People are coming up to the law school because they don’t have anywhere else to go. The school is sending buses into town to pick up students and bring them back to campus so they have somewhere safe to stay.”

The tornado was only the latest in a series that have struck the southern United States this week, causing heavy rains and flooding in an area stretching from Texas to Georgia, officials said Wednesday.

By Wednesday, the storms, which started Monday evening, had also left more than 50,000 people without power from East Texas to Memphis and destroyed scores of homes as the system moved east into Mississippi, Alabama and Georgia. The storms were expected to weaken before moving into the Carolinas and up the Eastern Seaboard on Thursday and Friday, according to the National Weather Service.

“Folks in the South should be getting some relief,” said Tom Bradshaw, a meteorologist with the service.

By Wednesday afternoon, Arkansas and Alabama had declared states of emergency after scores of buildings suffered significant damage, including many that had their roofs sheared off.

Wind speeds have reached 135 miles per hour, and mobile homes have been tossed about like toys, Mr. Bradshaw said. Accompanying rains and flash flooding have hit northern Arkansas especially hard, killing at least six people since Monday. Some parts of northern Arkansas have received 20 inches of rain during the past four days.

On Wednesday, a levee on the Black River in northeastern Arkansas failed, flooding local highways but causing no fatalities, officials said.

One of the victims killed this week was a Louisiana police officer who died Tuesday night in Mississippi on a camping trip after he was struck by a tree limb ripped off by high winds, emergency officials in Mississippi said. The officer’s name has not yet been released.

Jim Noles contributed reporting from Birmingham, Ala.

A version of this article appears in print on April 28, 2011, on page A1 of the New York edition with the headline: Storms Smash Across South; Dozens Killed. Order Reprints|Today's Paper|Subscribe